Heat exchanger

ABSTRACT

A heat exchanger includes: a pipe forming a flow path through which a first fluid is fed; a pair of partition plates provided at an interval in an extending direction of the flow path to block the flow path, to partition a closed space at a portion of the flow path; a plurality of heat transfer tubes having a tubular shape with both ends being open, extending so as to penetrate the pair of partition plates, and arranged side by side with intervals therebetween; a feeding part configured to feed a second fluid from an outside of the pipe to the closed space; and a discharging part configured to discharge the second fluid in the closed space to the outside of the pipe.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger.

Priority is claimed on Japanese Patent Application No. 2020-214438, filed Dec. 24, 2020, the content of which is incorporated herein by reference.

BACKGROUND ART

In a heat engine including an internal combustion engine and an external combustion engine, heat energy is generated by burning fuels, and the heat energy is extracted as, for example, rotational energy of an output shaft. At this time, high-temperature exhaust gas is generated in the heat engine. As a measure for effectively utilizing the heat energy of the exhaust gas, it is conceivable to install a heat exchanger in an exhaust gas flow path.

Conventionally, a heat exchanger has commonly included a plurality of heat transfer tubes and a fin provided in each heat transfer tube. In this type of heat exchanger, a heat medium flows inside the heat transfer tube, and the other medium flows outside the heat transfer tube. As a result, heat is exchanged between the two media via the fin.

CITATION LIST Patent Document

-   [Patent Document 1] -   Japanese Unexamined Patent Application, First Publication No.     2010-223520

SUMMARY OF INVENTION Technical Problem

Meanwhile, in recent years, there has been a demand for reduction in size of various devices including the heat engine described above. Therefore, it is necessary to significantly reduce the size of the heat exchanger.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a heat exchanger with a smaller size.

Solution to Problem

In order to solve the problems, a heat exchanger according to the present disclosure includes: a pipe forming a flow path through which a first fluid is fed; a pair of partition plates provided at an interval in an extending direction of the flow path to block the flow path, to partition a closed space at a portion of the flow path; a plurality of heat transfer tubes having a tubular shape with both ends being open, extending so as to penetrate the pair of partition plates, and arranged side by side with intervals therebetween; a feeding part configured to feed a second fluid from an outside of the pipe to the closed space; and a discharging part configured to discharge the second fluid in the closed space to the outside of the pipe.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide a heat exchanger with a smaller size.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration of a heat exchanger according to a first embodiment of the present disclosure.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 .

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1 .

FIG. 4 is a cross-sectional view showing a configuration of a heat exchanger according to a second embodiment of the present disclosure.

FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4 .

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4 .

FIG. 7 is a cross-sectional view showing a configuration of a heat transfer tube according to a third embodiment of the present disclosure.

FIG. 8 is a cross-sectional view showing a configuration of a heat exchanger according to a fourth embodiment of the present disclosure.

FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8 .

FIG. 10 is an enlarged cross-sectional view of a heat transfer tube according to a fifth embodiment of the present disclosure.

FIG. 11 is an enlarged cross-sectional view showing a modified example of the heat transfer tube according to the fifth embodiment of the present disclosure.

FIG. 12 is a perspective view showing the modified example of the heat transfer tube according to the fifth embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS First Embodiment

(Configuration of Heat Exchanger)

Hereinafter, a heat exchanger 100 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 3 . As shown in FIG. 1 , the heat exchanger 100 is positioned in the midway of a pipe 1. The pipe 1 forms a flow path through which exhaust gas (first fluid) discharged from a heat engine such as an engine flows. In an example of FIG. 1 , the pipe 1 includes a straight tubular pipe body 11 and elbow parts 10 each provided at both end portions of the pipe body 11. The elbow part 10 forms a curved portion, and an inside of the elbow part 10 is provided with a plurality of vanes 4 for guiding a flowing direction of the exhaust gas to the curved portion. Each vane 4 is curved along a curve of the elbow part 10. The plurality of vanes 4 are provided at an interval in a direction intersecting an extending direction of the elbow part 10.

Inside of the pipe body 11, a plurality of heat transfer tubes 3 are arranged side by side with intervals therebetween. The exhaust gas flows inside the heat transfer tube 3. As shown in FIG. 2 , the heat transfer tube 3 is a tube having a cross section of hexagonal shape, and both ends of the heat transfer tube 3 are open. The inside of the heat transfer tube 3 is a first flow path F1. In addition, the plurality of the heat transfer tubes 3 are adjacent to each other so that outer surfaces thereof are in parallel to each other, and arranged so as to have a hexagonal shape as a whole. A space formed between the heat transfer tubes 3 is a second flow path F2 through which water flows as a second fluid.

A feeding part 21 as an inlet side header and a discharging part 22 as an outlet side header are provided on both end portions of the pipe body 11. The feeding part 21 is provided for feeding water introduced from the outside into the pipe 1, and the discharging part 22 is provided for discharging the water that has passed through the pipe 1 to the outside. More specifically, the discharging part 22 is provided on an end portion at an upstream side (a side where the first fluid flows) of the pipe 1, and the feeding part 21 is provided on an end portion at a downstream side of the pipe 1. The feeding part 21 and the discharging part 22 have the same configuration as each other except for a flowing direction of the fluid. Thus, a configuration of the discharging part 22 will be typically described herein with reference to FIG. 3 .

As shown in FIG. 3 , the discharging part 22 includes a cylindrical discharging part body 22H that covers the end portions of the plurality of heat transfer tubes 3 from the outside, and a partition plate 20 that blocks an opening of the discharging part body 22H. An opening H for discharging water to the outside is formed in a portion of the discharging part body 22H in a circumferential direction. The flow path formed by the pipe body 11 is blocked from both sides by the partition plate 20 of the discharging part 22 and the partition plate 20 of the feeding part 21. A space partitioned by a pair of partition plates 20 is a closed space V. Further, the heat transfer tube 3 extends so as to penetrate the partition plate 20. That is, in the closed space V, the first flow path F1 formed by the heat transfer tube 3 and the second flow path F2 formed by a gap between the heat transfer tubes 3 extend in parallel.

Each component of the heat exchanger 100 with the configuration described above is formed by a 3D printer technique represented by additive modeling (AM), which is desirable. Further, as a material for forming the heat exchanger 100, titanium or SUS is preferably used.

Effect

Next, an operation of the heat exchanger 100 will be described. In operating the heat exchanger 100, first, water as a second fluid is fed into the closed space V through the feeding part 21. At this time, the heat engine is operated, high-temperature exhaust gas thus flows in the heat transfer tube 3 as a first fluid. Further, inside the pipe body 11, the water flows toward a direction opposite to the flowing direction of the exhaust gas through the gap (second flow path F2) between the heat transfer tubes 3. While the water is flowing through the second flow path F2, heat exchange occurs with the exhaust gas through a wall surface of the heat transfer tube 3. As a result, the temperature of the water becomes high, and the water is fed into an external device via the discharging part 22. On the other hand, the temperature of the exhaust gas becomes low, and the exhaust gas flows away toward the downstream side in the pipe 1. As such a phenomenon continuously occurs, the heat exchange between water and exhaust gas is performed.

According to the above configuration, the closed space V is formed by the partition plate 20 in the middle of extension of the pipe 1. Heat exchange is performed between the first fluid flowing through the heat transfer tube 3 and the second fluid flowing outside the heat transfer tube 3 in the closed space V. As described above, according to the above configuration, the heat exchanger 100 can be provided in the middle of extension of the pipe 1 without changing an extending direction of the pipe 1 and without greatly enlarging an outer diameter of the pipe 1. Accordingly, it is possible to save a space for disposing the heat exchanger 100. As a result, the heat exchanger 100 can be easily provided even in a narrow region in which the heat exchanger 100 is difficult to be provided in the related art.

Moreover, according to the above configuration, the heat transfer tube 3 has a cross section of a polygonal (hexagonal) shape. Therefore, it is possible to further improve the efficiency of heat exchange because a wetted area of an inner surface of the heat transfer tube 3 is expanded, as compared with a case where the heat transfer tube 3 has a cross section of a quadrangular shape. In addition, more preferably, when the cross section of the heat transfer tube 3 has a circular shape, it is possible to further enlarge the wetted area. When the shape of the cross section is a circular shape, there is a disadvantage of decreased filling density of the fluid, and thus it is desirable to determine the shape of the heat transfer tube according to the overall balance.

Moreover, according to the above configuration, since the water as the second fluid flows into the interval between the heat transfer tubes 3, it is possible to secure a large contact area with the heat transfer tube 3. As a result, it is possible to further improve the efficiency of heat exchange while reducing the size of the heat exchanger 100.

The first embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

Second Embodiment

Next, a second embodiment of the present disclosure will be described with reference to FIGS. 4 to 6 . Components similar to those of the first embodiment are denoted by the same reference signs, and repeated description will not be provided. As shown in FIG. 4 , in the present embodiment, there is further provided a blocking part 5 blocking only a portion of the interval between the heat transfer tubes 3. A plurality of the blocking parts 5 are provided at an interval in an extending direction of the pipe body 11. In addition, the blocking parts 5 adjacent to each other have different regions to be blocked. More specifically, one blocking part 5 of the adjacent blocking parts 5 blocks only an upper portion in the pipe body 11 as shown in FIG. 5 . As shown in FIG. 6 , the other blocking part 5 blocks only a lower portion in the pipe body 11. By alternately arranging such blocking parts 5, the second flow path F2 in the pipe body 11 extends in a meandering manner. That is, the blocking part 5 functions as a baffle plate.

According to the above configuration, the blocking part 5 changes a flowing direction of the water in the closed space V. Since the regions blocked by the adjacent blocking parts 5 are different, the water flows in a meandering manner while passing through the plurality of blocking parts 5. As a result, because the water is uniformly distributed in the closed space V, the contact area between the water and the heat transfer tube 3 is expanded, such that it is possible to further improve the efficiency of heat exchange between the water and the exhaust gas.

The second embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the second embodiment, an example in which the blocking part 5 blocks the upper portion or lower portion in the closed space V has been described. However, the mode of the blocking part 5 is not limited thereto, and it is possible to adopt a configuration in which the blocking part 5 blocks left and right sides of the pipe 1 in the extending direction of the pipe 1. In this case, the water can flow smoothly while meandering in a horizontal direction without against gravity, such that the efficiency of heat exchange can be further improved. Particularly, this configuration is suitable when it is assumed that the fluid contains a component having a low density and stays in the middle of the flow path.

Third Embodiment

Subsequently, a third embodiment of the present disclosure will be described with reference to FIG. 7 . Components similar to those of the above-described embodiments are denoted by the same reference signs, and a repeated description will not be provided. As shown in FIG. 7 , in the present embodiment, a supporting part 6 is provided between the heat transfer tubes 3 adjacent to each other. The supporting part 6 connects outer surfaces of the heat transfer tubes 3 to each other. Further, although not shown in detail, the supporting part 6 is provided on a portion of the heat transfer tube 3 in the extending direction.

According to the above configuration, the supporting part 6 can suppress displacement and deformation of the heat transfer tube 3. As a result, the heat exchanger 100 can be stably operated for a longer period of time.

The third embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, a configuration can be adopted in which a through-hole is formed in the supporting part 6 and the fluid flows through the through-hole. In this case, the supporting part 6 can suppress hindrance of fluid flow.

Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be described with reference to FIGS. 8 and 9 . Components similar to those of the above-described embodiments are denoted by the same reference signs, and repeated description will not be provided. As shown in FIG. 9 , in the present embodiment, the plurality of heat transfer tubes 3 are configured such that the heat transfer tube 3 disposed in a region having a smaller flow rate has a larger cross-sectional area of the flow path. Specifically, in a case where the elbow part 10 of the pipe 1 is vertically curved, a heat transfer tube 3A has a larger cross-sectional area of the flow path as it is positioned upward and a heat transfer tube 3B has a smaller cross-sectional area of the flow path as it is positioned downward.

For example, in a case where the pipe 1 has a curved portion such as the elbow part 10 on the upstream side of the pipe 1, the flow rate of the exhaust gas tends to be larger as the heat transfer tube 3 is directed toward an outer peripheral side of the curved portion due to inertial force, and the flow rate tends to be smaller as the heat transfer tube 3 is directed toward an inner peripheral side of the curved portion. According to the above configuration, the heat transfer tube 3 has a larger cross-sectional area of the flow path as it is disposed in the region having a smaller flow rate. As a result, even when flow rate distribution is non-uniform as described above, it is possible to correct the configuration and allow the exhaust gas to flow uniformly over the entire plurality of heat transfer tubes 3. As a result, the efficiency of the heat exchanger 100 can be further improved.

The fourth embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

Fifth Embodiment

Subsequently, a fifth embodiment of the present disclosure will be described with reference to FIG. 10 . Components similar to those of the above-described embodiments are denoted by the same reference signs, and repeated description will not be provided. As shown in FIG. 10 , in the present embodiment, a plurality of fins 3F are further provided on the inner surface of the heat transfer tube 3. The fins 3F protrude from the inner surface toward the inner peripheral side of the heat transfer tube 3, and extend over the entire region of the heat transfer tube 3 in the extending direction. The plurality of such fins 3F are arranged at an interval along the inner surface. In addition, in the present embodiment, the fin 3F extends linearly in the extending direction of the heat transfer tube 3. When the length of one side of a hexagon forming the cross section of the heat transfer tube 3 is 6 mm, for example, it is desirable for the protruding height of the fin 3F to be about 2 mm, and the width of the fin 3F is about 1 mm.

According to the above configuration, since the contact area between the exhaust gas and the heat transfer tube 3 is expanded by including the fins 3F, the efficiency of heat exchange can be further improved. Further, since the fin 3F has a minute dimension as described above, it is difficult for dust or soot contained in the exhaust gas flowing in the heat transfer tube 3 to accumulate. As a result, the heat exchanger 100 can be stably operated for a longer period of time.

The fifth embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

For example, an example of the fin 3F extending linearly in the fifth embodiment has been described. However, as shown in FIGS. 11 and 12 , a fin 3F′ may extend so as to turn along the inner surface from the upstream side to the downstream side of the heat transfer tube 3 in the extending direction. In FIGS. 11 and 12 , a tip A1 and a base end A2 of the fin 3F′ extend so as to turn about the central axis of the heat transfer tube 3 from one side of the heat transfer tube 3 in the circumferential direction toward the other side. Similar to the fifth embodiment, a configuration can be adopted in which a plurality of such fins 3F′ are arranged at an interval along the inner surface.

According to the above configuration, since the fin 3F′ extends so as to turn along the inner surface, a turning flow component is added to the flow of the exhaust gas inside the heat transfer tube 3. As a result, a staying time of the exhaust gas inside the heat transfer tube 3 becomes long, such that the efficiency of heat exchange can be further improved. Further, since the exhaust gas accompanies the turning flow component, it is possible to suppress generation of deposits such as dust and soot on the fin 3F. As a result, the heat exchanger 100 can be stably operated for a longer period of time.

Appendix

The heat exchanger 100 described in each embodiment is grasped as follows, for example.

(1) A heat exchanger 100 according to a first aspect includes: a pipe 1 forming a flow path through which a first fluid is fed; a pair of partition plates 20 provided at an interval in an extending direction of the flow path to block the flow path, to partition a closed space V at a portion of the flow path; a plurality of heat transfer tubes 3 having a tubular shape with both ends being open, extending so as to penetrate the pair of partition plates 20, and arranged side by side with intervals therebetween; a feeding part 21 configured to feed a second fluid from an outside of the pipe 1 to the closed space V; and a discharging part 22 configured to discharge the second fluid in the closed space V to the outside of the pipe 1.

According to the above configuration, the closed space V is formed by the partition plate 20 in the middle of extension of the pipe 1. Heat exchange is performed between the first fluid flowing through the heat transfer tube 3 and the second fluid flowing outside the heat transfer tube 3 in the closed space V. As described above, according to the above configuration, the heat exchanger 100 can be provided in the middle of extension of the pipe 1 without changing the extending direction of the pipe 1 and without greatly enlarging an outer diameter of the pipe 1. Accordingly, it is possible to save space for disposing the heat exchanger 100.

(2) In the heat exchanger 100 according to a second aspect, the heat transfer tube 3 may have a cross section of a polygonal shape when viewed in the extending direction.

According to the above configuration, since a wetted area in an inner surface of the heat transfer tube 3 is expanded, it is possible to further improve the efficiency of heat exchange.

(3) In the heat exchanger 100 according to a third aspect, the second fluid may be configured to flow through the interval between the plurality of heat transfer tubes 3 in the closed space V.

According to the above configuration, since the second fluid flows into the interval between the heat transfer tubes 3, it is possible to secure a large contact area with the heat transfer tube 3. As a result, it is possible to further improve the efficiency of heat exchange while reducing the size of the heat exchanger 100.

(4) The heat exchanger 100 according to a fourth aspect may further include a blocking part 5 blocking only a portion of the interval between the heat transfer tubes 3, in which a plurality of the blocking parts 5 may be provided at an interval in the extending direction, and the blocking parts 5 adjacent to each other may have the blocking regions different from each other.

According to the above configuration, the blocking part 5 changes a flowing direction of the second fluid in the closed space V. Since the regions blocked by the adjacent blocking parts 5 are different, the second fluid flows in a meandering manner while passing through the plurality of blocking parts 5. As a result, since the second fluid is uniformly distributed in the closed space V, it is possible to further improve the efficiency of heat exchange.

(5) The heat exchanger 100 according to a fifth aspect may further include a supporting part 6 provided between the heat transfer tubes 3.

According to the above configuration, the supporting part 6 can suppress displacement and deformation of the heat transfer tube.

(6) In the heat exchanger 100 according to a sixth aspect, the plurality of heat transfer tubes 3 may be configured such that the heat transfer tube 3 disposed in a region having a smaller flow rate has a larger cross-sectional area of the flow path.

For example, in a case where the pipe 1 has a curved portion on the upstream side of the pipe 1, the flow rate of the first fluid tends to be larger as the heat transfer tube 3 is directed toward an outer peripheral side of the curved portion due to inertial force, and the flow rate tends to be smaller as the heat transfer tube 3 is directed toward an inner peripheral side of the curved portion. According to the above configuration, the heat transfer tube 3 has a larger cross-sectional area of the flow path as it is disposed in the region having a smaller flow rate. As a result, even when flow rate distribution is non-uniform as described above, it is possible to correct the configuration and allow the first fluid to flow uniformly over the entire plurality of heat transfer tubes 3.

(7) The heat exchanger 100 according to a seventh aspect may further include a plurality of fins 3F protruding from an inner surface of the heat transfer tube 3, extending in the extending direction, and provided at an interval along the inner surface.

According to the above configuration, since a contact area with the first fluid is expanded by the fin 3F, it is possible to further improve the efficiency of heat exchange.

(8) In the heat exchanger 100 according to an eighth aspect, the fin 3F′ may extend so as to turn along the inner surface from an upstream side to a downstream side in the extending direction.

According to the above configuration, since the fin 3F′ extends so as to turn along the inner surface, a turning flow component is added to the first fluid inside the heat transfer tube 3. As a result, a staying time of the first fluid inside the heat transfer tube 3 becomes long, such that the efficiency of heat exchange can be further improved. Further, since the exhaust gas accompanies the turning flow component, it is possible to suppress generation of deposits such as dust on the fin 3F′.

INDUSTRIAL APPLICABILITY

According to the present disclosure, it is possible to provide a heat exchanger with a smaller size.

REFERENCE SIGNS LIST

-   -   100: Heat exchanger     -   1: Pipe     -   3, 3A, 3B: Heat transfer tube     -   3F, 3F′: Fin     -   4: Vane     -   5: Blocking part     -   6: Supporting part     -   10: Elbow part     -   11: Pipe body     -   20: Partition plate     -   21: Feeding part     -   22: Discharging part     -   22H: Discharging part body     -   F1: First flow path     -   F2: Second flow path     -   H: Opening     -   V: Closed space 

1-8. (canceled)
 9. A heat exchanger comprising: a pipe forming a flow path through which a first fluid is fed; a pair of partition plates provided at an interval in an extending direction of the flow path to block the flow path, to partition a closed space at a portion of the flow path; a plurality of heat transfer tubes having a tubular shape with both ends being open, extending so as to penetrate the pair of partition plates, and arranged side by side with intervals therebetween; a feeding part configured to feed a second fluid from an outside of the pipe to the closed space; and a discharging part provided on an upstream side of a flow of the first fluid with respect to the feeding part, and configured to discharge the second fluid in the closed space to the outside of the pipe, wherein the heat transfer tube has a cross section of a hexagonal shape between the pair of partition plates in the closed space, when viewed in the extending direction, and the heat exchanger further includes a plurality of fins protruding from an inner surface of the heat transfer tube, extending in the extending direction, and provided at an interval along the inner surface.
 10. The heat exchanger according to claim 9, wherein the heat transfer tube among the plurality of heat transfer tubes is configured to have a larger cross-sectional area of the flow path as the heat transfer tube is disposed in a region having a smaller flow rate.
 11. A heat exchanger comprising: a pipe forming a flow path through which a first fluid is fed; a pair of partition plates provided at an interval in an extending direction of the flow path to block the flow path, to partition a closed space at a portion of the flow path; a plurality of heat transfer tubes having a tubular shape with both ends being open, extending so as to penetrate the pair of partition plates, and arranged side by side with intervals therebetween; a feeding part configured to feed a second fluid from an outside of the pipe to the closed space; and a discharging part configured to discharge the second fluid in the closed space to the outside of the pipe, wherein the heat transfer tube has a cross section of a polygonal shape, when viewed in the extending direction, the heat exchanger further includes a plurality of fins protruding from an inner surface of the heat transfer tube, extending in the extending direction, and provided at intervals along the inner surface, and the plurality of heat transfer tubes are configured such that the heat transfer tube disposed in a region having a smaller flow rate has a larger cross-sectional area of the flow path.
 12. The heat exchanger according to claim 9, wherein the fin extends so as to turn along the inner surface from an upstream side to a downstream side in the extending direction.
 13. The heat exchanger according to claim 9, wherein the second fluid is configured to flow through the interval between the plurality of heat transfer tubes in the closed space.
 14. The heat exchanger according to claim 9, further comprising: a blocking part blocking only a portion of the interval between the heat transfer tubes, wherein a plurality of the blocking parts are provided at an interval in the extending direction, and the blocking parts adjacent to each other have the blocking regions different from each other.
 15. The heat exchanger according to claim 9, further comprising: a supporting part provided between the heat transfer tubes. 